Nucleosides typically include a nitrogenous base, such as adenine, cytosine, thymine, guanine or uracil, and a sugar moiety, such as ribose or deoxyribose. The sugar moiety can be linked to one or more phosphoryl groups to form a nucleoside phosphate. The nucleoside phosphates can be linked to each other, e.g., through phosphodiester bonds, to form strands of linked nucleoside phosphates. Researchers have long desired fluorescent nucleosides to probe nucleic acid structure. Fluorescent nucleoside bases also would be useful in the analysis of nucleic acid-protein interactions.
It is an object of the present invention to provide a novel fluorescent nitrogenous base that possesses properties that allow it to substitute for at least one of the naturally occurring nitrogenous bases. It is a particular object of at least some examples of the invention to provide a fluorescent nucleoside that possesses properties that allow it to substitute for cytidine. Additional objects and aspects of the invention will be apparent from the following disclosure.